The singer's debut album '+' knocked Adele's '21' from the top of the pile, but only sold 20,607 copies in the process. This is the lowest weekly sales for a Number One album since the Levellers' album 'Zeitgeist' topped the charts in 1995 with sales of 13,885.

Speaking to NME, a spokesman for HMV said that a combination of people being careful with their cash after Christmas and a lack of new releases led to the major slump in sales.

They said: "January is often the quietest month as people tend to be cautious with their spending to pay off Christmas, so although chart sales weren't particularly high, these sorts of numbers shouldn't come as that much of a surprise, especially when you consider there were hardly any new albums out last week - which you always need if you're going to galvanize public and media interest."

The spokesman added that sales will pick up this week, as a number of hotly anticipated new releases, including Lana Del Rey's 'Born To Die' and the impending arrival of Valentine's Day and the Brit Awards will see things return to normal.

They added: "It [sales] should all change this week, though, as people got paid at the weekend, and there are some much anticipated new releases finally coming out, not least Lana Del Rey. With Valentine's Day, the NME Awards Tour and the BRITs coming up soon, things should start to pick up quite a bit."